Improved Production Efficiency of Virus-Like Particles by the Baculovirus Expression Vector System.

Vaccines based on virus-like particles (VLPs) have proven effective in humans and animals. In this regard, the baculovirus expression vector system (BEVS) is one of the technologies of choice to generate such highly immunogenic vaccines. The extended use of these vaccines for human and animal populations is constrained because of high production costs, therefore a significant improvement in productivity is crucial to ensure their commercial viability. Here we describe the use of the previously described baculovirus expression cassette, called TB, to model the production of two VLP-forming vaccine antigens in insect cells. Capsid proteins from porcine circovirus type 2 (PCV2 Cap) and from the calicivirus that causes rabbit hemorrhagic disease (RHDV VP60) were expressed in insect cells using baculoviruses genetically engineered with the TB expression cassette. Productivity was compared to that obtained using standard counterpart vectors expressing the same proteins under the control of the polyhedrin promoter. Our results demonstrate that the use of the TB expression cassette increased the production yields of these vaccine antigens by around 300% with respect to the standard vectors. The recombinant proteins produced by TB-modified vectors were fully functional, forming VLPs identical in size and shape to those generated by the standard baculoviruses, as determined by electron microscopy analysis. The use of the TB expression cassette implies a simple modification of the baculovirus vectors that significantly improves the cost efficiency of VLP-based vaccine production, thereby facilitating the commercial viability and broad application of these vaccines for human and animal health.

Prospective double-blind clinical trial evaluating the effectiveness of Bromelain in the third molar extraction postoperative period

OBJECTIVES: To evaluate the anti-inflammatory and analgesic effect of Bromelain (pineapple extract) administered orally in the postoperative after extraction of impacted lower molars. Study DESIGN: This is a prospective, placebo-controlled, unicentric, double-blind study; the sample size was 34 patients. The pre and postoperative outcomes, evaluated on the third (D3) and eighth day (D8), included inflamtion, pain and oral aperture, as well as the need for analgesics. One group received Bromelain 150mg per day for three days and 100mg on days 4 to 7. The other group received placebo in the same dosage. All outcomes werrecorded quantitatively and analyzed with the Mann-Whitney U test for independent samples. RESULTS: Although there were no statistically significant differences between the treatment groups, a trend towards less inflammation and improved oral aperture was observed in the group that received Bromelain, compared to the group that received placebo. This trend can be attributed completely to random reasons, since there is no statistical difference in the results. CONCLUSIONS: Further studies are necessary to analyze different administration patterns and doses of Bromelain for the use in the postoperative of impacted third molars

Head-to-head comparison of three vaccination strategies based on DNA and raw insect-derived recombinant proteins against Leishmania.

Parasitic diseases plague billions of people among the poorest, killing millions annually, and causing additional millions of disability-adjusted life years lost. Leishmaniases affect more than 12 million people, with over 350 million people at risk. There is an urgent need for efficacious and cheap vaccines and treatments against visceral leishmaniasis (VL), its most severe form. Several vaccination strategies have been proposed but to date no head-to-head comparison was undertaken to assess which is the best in a clinical model of the disease. We simultaneously assayed three vaccination strategies against VL in the hamster model, using KMPII, TRYP, LACK, and PAPLE22 vaccine candidate antigens. Four groups of hamsters were immunized using the following approaches: 1) raw extracts of baculovirus-infected Trichoplusia ni larvae expressing individually one of the four recombinant proteins (PROT); 2) naked pVAX1 plasmids carrying the four genes individually (DNA); 3) a heterologous prime-boost (HPB) strategy involving DNA followed by PROT (DNA-PROT); and 4) a Control including empty pVAX1 plasmid followed by raw extract of wild-type baculovirus-infected T. ni larvae. Hamsters were challenged with L. infantum promastigotes and maintained for 20 weeks. While PROT vaccine was not protective, DNA vaccination achieved protection in spleen. Only DNA-PROT vaccination induced significant NO production by macrophages, accompanied by a significant parasitological protection in spleen and blood. Thus, the DNA-PROT strategy elicits strong immune responses and high parasitological protection in the clinical model of VL, better than its corresponding naked DNA or protein versions. Furthermore, we show that naked DNA coupled with raw recombinant proteins produced in insect larvae biofactories -the cheapest way of producing DNA-PROT vaccines- is a practical and cost-effective way for potential "off the shelf" supplying vaccines at very low prices for the protection against leishmaniases, and possibly against other parasitic diseases affecting the poorest of the poor.

Homodimeric bis-quaternary heterocyclic ammonium salts as potent acetyl- and butyrylcholinesterase inhibitors: a systematic investigation of the influence of linker and cationic heads over affinity and selectivity.

A molecular library of quaternary ammonium salts (QASs), mainly composed of symmetrical bis-quaternary heterocyclic bromides exhibiting choline kinase (ChoK) inhibitory activity, were evaluated for their ability to inhibit acetyl- and butyrylcholinesterase (AChE and BChE, respectively). The molecular framework of QASs consisted of two positively charged heteroaromatic (pyridinium or quinolinium) or sterically hindered aliphatic (quinuclidinium) nitrogen rings kept at an appropriate distance by lipophilic rigid or semirigid linkers. Many homodimeric QASs showed AChE and BChE inhibitory potency in the nanomolar range along with a low enzymatic selectivity. Computational studies on AChE, BChE, and ChoK allowed identification of the key molecular determinants for high affinity and selectivity over either one of the three enzymes and guided the design of a hybrid bis-QAS (56) exhibiting the highest AChE affinity (IC(50) = 15 nM) and selectivity over BChE and ChoK (SI = 50 and 562, respectively) and a promising pharmacological potential in myasthenia gravis and neuromuscular blockade.

Humoral and in vivo cellular immunity against the raw insect-derived recombinant Leishmania infantum antigens KMPII, TRYP, LACK, and papLe22 in dogs from an endemic area.

Leishmania infantum causes visceral leishmaniasis, a severe zoonotic and systemic disease that is fatal if left untreated. Identification of the antigens involved in Leishmania-specific protective immune response is a research priority for the development of effective control measures. For this purpose, we evaluated, in 27 dogs from an enzootic zone, specific humoral and cellular immune response by delayed-type hypersensitivity (DTH) skin test both against total L. infantum antigen and the raw Trichoplusia ni insect-derived kinetoplastid membrane protein-11 (rKMPII), tryparedoxin peroxidase (rTRYP), Leishmania homologue of receptors for activated C kinase (rLACK), and 22-kDa potentially aggravating protein of Leishmania (rpapLe22) antigens from this parasite. rTRYP induced the highest number of positive DTH responses (55% of leishmanin skin test [LST]-positive dogs), showing that TRYP antigen is an important T cell immunogen, and it could be a promising vaccine candidate against this disease. When TRYP-DTH and KMPII-DTH tests were evaluated in parallel, 82% of LST-positive dogs were detected, suggesting that both antigens could be considered as components of a standardized DTH immunodiagnostic tool for dogs.

From 5-fluorouracil acyclonucleosides to benzo-fused six- and seven-membered rings linked to pyrimidine and purine bases: the shift from differentiating anticancer agents to apoptotic inducers.

BACKGROUND: (RS)-1-{[3-(2-Hydroxyethoxy)-1-isopropoxy]propyl}-5-fluorouracil proved to be a good differentiating agent against rhabdomyosarcoma cells. OBJECTIVE: As lipophilicity is known to affect the anticancer activity, the synthesis of a wide range of 5-fluorouracil derivatives linked to benzo-fused seven-membered rings was undertaken. METHODS: The decision was then made to change 5-fluorouracil for uracil, with the prospect of finding an antiproliferative agent endowed with a new mechanism of action. Later on, pyrimidines were substituted for purines. Completing a structure-activity relationship study, a series of isosteric seven-membered derivatives were prepared. RESULTS/CONCLUSION: Finally, molecules were designed in which both structural entities (such as the benzoheterocycle and the purine) were linked through a strong C-C bond. The anticancer activity for the most active compounds was correlated with their capability to induce apoptosis.

Analysis of the precursor rRNA fractions of rapidly growing mycobacteria: quantification by methods that include the use of a promoter (rrnA P1) as a novel standard.

Mycobacterial species are able to control rRNA production through variations in the number and strength of promoters controlling their rrn operons. Mycobacterium chelonae and M. fortuitum are members of the rapidly growing mycobacterial group. They carry a total of five promoters each, encoded, respectively, by one and two rrn operons per genome. Quantification of precursor rrn transcriptional products (pre-rrn) has allowed detection of different promoter usage during cell growth. Bacteria growing in several culture media with different nutrient contents were compared. Balanced to stationary phases were analyzed. Most promoters were found to be used at different levels depending on the stage of bacterial growth and the nutrient content of the culture medium. Some biological implications are discussed. Sequences of the several promoters showed motifs that could be correlated to their particular level of usage. A product corresponding to the first rrnA promoter in both species, namely, rrnA P1, was found to contribute at a low and near-constant level to pre-rRNA synthesis, regardless of the culture medium used and the stage of growth analyzed. This product was used as a standard to quantitate rRNA gene expression by real-time PCR when M. fortuitum infected macrophages. It was shown that this bacterium actively synthesizes rRNA during the course of infection and that one of its rrn operons is preferentially used under such conditions.

Distamycin A as stem of DNA minor groove alkylating agents.

Analogues of naturally occurring antitumor agents, such as distamycin A, which bind in the minor groove of DNA, represent a new class of anticancer compounds currently under investigation. Distamycin A has driven researcher's attention not only for their biological activity, but also for its non intercalative binding to the minor groove of double-stranded B-DNA, where it forms strong reversible complex preferentially at the nucleotide sequences consisting of 4-5 adjacent AT base pairs. The pyrrole-amide skeleton of distamycin A has been also used as DNA sequence selective vehicles for the delivery of alkylating functions to DNA targets, leading to a sharp increase of its cytotoxicity, in comparison to that, very weak, of distamycin itself. In the last few years, several hybrid compounds, in which known antitumor derivatives or simple active moieties of known antitumor agents have been tethered to distamycin frames, have been designed, synthesized and tested. Several efforts have been made to modify DNA sequence selectivity and stability of the distamycin and the structural modifications have been based on replacement of pyrrole by other heterocycles and/or benzoheterocycles obtaining a novel class of minor groove binding molecules called lexitropsins. The role of the amidino moiety, by means of the substitution with various groups, which includes ionizable, acid or basic, and non-ionizable groups, has been also studied. The synthesis of a hybrid deriving among the combination of the distamycin A and naturally occurring alkylating agent has been also reported. Several classes of distamycin derivatives that have been reported in the published literature have been described in this review article.

Design, synthesis and in vitro cytotoxicity of a cis-dichloroplatinum (II) complex linked to the minor groove binder stallimycin.

Two potentially hydrophilic platinum (II) complexes 10 and 11 bound to the minor groove binder stallimycin (distamycin A, CAS 636-47-5) by L-cysteine and D,L-2,3-diaminopropionic acid have been synthesized. The in vitro cytotoxicity of both these complexes was evaluated against several cell lines. None of the synthesized platinum complexes showed greater activity than that of cisplatin (cis-DDP, 1) (CAS 15663-27-1). Interestingly, the free ligands 6 and 9 were more active than the related platinum complexes 10 and 11, respectively, with respect to RAJI, CCRF-CEM and MOLT-4 human leukaemia cell lines.

Synthesis and biological effects of novel 2-amino-3-naphthoylthiophenes as allosteric enhancers of the A1 adenosine receptor.

The current study describes the synthesis and biological evaluation of a novel series of 2-amino-3-naphthoylthiophenes, with variable modifications at the 4- and 5-position of the thiophene as well as the naphthoyl ring. Allosteric enhancer activity was measured in several ways: (1) evaluating the effect on forskolin-stimulated cAMP accumulation in the presence of an A(1)-adenosine agonist (CPA) in Chinese hamster ovary (CHO) cells expressing the cloned human A(1)-adenosine receptor (hA(1)AR); (2) ability of these compounds to displace the binding of [(3)H]DPCPX, [(3)H]ZM 241385, and [(3)H]MRE 3008F20 to the ligand binding site of CHO cells expressing the hA(1), hA(2A), and hA(3) adenosine receptors, respectively; (3) effect on the binding of [(3)H]CCPA to membranes from CHO cells expressing hA(1)AR, to rat brain and human cortex membrane preparations containing native adenosine A(1) receptors; (4) kinetics of the dissociation of [(3)H]CCPA from CHO-hA1 membranes. The pharmacological assays compared the various activities to that of the reference compound PD 81,723 (compound 1). Several compounds appeared to be better than PD 81,723 to enhance the effect of CPA (and thus reduce cAMP content) in the CHO:hA(1) assay. The effect of these compounds at a concentration of 10 microM was slightly greater than that of the same concentration of the PD 81,723 and substantially greater than that of PD 81,723 when responses to 1 microM of each compound were compared. These include compounds 23, 25-29, 31-34, 38, 39, 43, and 58. Cycloalkylthiophenes tended to be more potent then their 4,5-dimethyl analogues, and in the series of cycloalkylthiophenes, tetrahydrobenzo[b]thiophene derivatives appeared to be more potent than the dihydrocyclopentadien[b]thiophene counterparts. Some of the most potent compounds were tested at a concentration of 10 microM for their affinity as competitors to the antagonist binding site of CHO cells expressing hA(1), hA(2A), and hA(3) adenosine receptors. None inhibited binding at the hA(2A)AR, but most of them inhibited binding to the hA(1)AR to varying extents (0-19%) as well as to the hA(3)AR to a substantial degree (0-57%). At a concentration of 10 microM, the compounds 31, 34, 37, 38, and 39 were more active than PD 81,723 to increase the binding of [(3)H]CCPA to CHO:hA(1), human brain and rat cortex membranes. Compound 37 was the most active compound increasing the binding to CHO:hA(1), human brain, and rat cortex membranes by 149, 43, and 27%, respectively (51, 15, and 22%, respectively, for PD 81,723). A good correlation was found between the increments [(3)H]CCPA binding to A(1) receptors expressed in different systems. Unlike the effect on agonist binding, the tested compounds did not increase the binding of the antagonist [(3)H]DPCPX on hCHO-A(1) membranes. Ligand dissociation studies revealed that two compounds (22 and 39) were more potent than 1 to slow the dissociation of [(3)H]CCPA from CHO:hA(1)AR membranes. No clear-cut structure-activity relationship can be observed based on data from the functional assay, but we have identified several compounds, in particular 37 and 39, which appeared to be more potent than 1 and that may be selected for further development.

Synthesis, biological activity and molecular modeling studies of 1,2,3,4-tetrahydroisoquinoline derivatives as conformationally constrained analogues of KN62, a potent antagonist of the P2X7-receptor containing a tyrosine moiety.

A new series of ring constrained analogues of the P2X7 receptor antagonist KN62 (1-[N,O-bis(1,5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4- phenylpiperazine, CAS 127191-97-3) containing the 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid core with S configuration in position 3 was synthesised and their antagonist activities were tested on human macrophage cells. While KN62 is a potent antagonist of the P2X7 receptor, these novel compounds are weak antagonists of the purinergic P2X7 receptor and only one compound (5) showed appreciable activity as P2X7 antagonist, which was 30 times weaker than that reported for KN62. Along with compound 5, the derivatives 11 and 25 were the most active inhibitors in this synthesised series. A molecular modeling study confirmed that an extended rather than folded conformation seems to be crucial for the antagonistic activity at the P2X7 receptor.

Antimicrobial and antitumor activity of N-heteroimmine-1,2,3-dithiazoles and their transformation in triazolo-, imidazo-, and pyrazolopirimidines.

The reaction of Appel's salt with o-amino nitrile heterocycles 10-19 gave the corresponding 4-chloro-5-heteroimmine-1,2,3-dithiazoles 20-29 which were evaluated for their antibacterial, antifungal and antitumor activity. Although all these N-heteroimines were devoid of significant antibacterial activity, they showed significant antifungal activity. Moreover, the same derivatives represent highly versatile intermediates in heterocyclic synthesis, in fact the pyrazoleimino dithiazoles 20-26 can be converted in one step into 2-cyano derivatives of the corresponding 4-methoxy-pyrazolo[3,4-d]pyrimidines 30-35 by sodium methoxide in refluxing methanol. This provides a general and attractive route to 4-methoxy-6-cyano pyrazolo[3,4-d]pyrimidines from 1-substituted 5-amino pyrazoles 10-19 in two simple steps. Finally, the isosteric replacement of the pyrazole ring atoms to give the imidazole[3,4-d]pyrimidine and triazole [4,5-d] pyrimidine ring systems was examined.